Commit 736565d4 authored by David Kaplan's avatar David Kaplan Committed by Borislav Petkov (AMD)
Browse files

x86/bugs: Add attack vector controls for TAA 



Use attack vector controls to determine if TAA mitigation is required.

Signed-off-by: default avatarDavid Kaplan <david.kaplan@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-7-david.kaplan@amd.com
parent e3a88d4c

arch/x86/kernel/cpu/bugs.c

+8 −7
Original line number Diff line number Diff line
@@ -538,12 +538,13 @@ static void __init taa_select_mitigation(void) 
		return;

	}



	if (cpu_mitigations_off())

		taa_mitigation = TAA_MITIGATION_OFF;



	/* Microcode will be checked in taa_update_mitigation(). */

	if (taa_mitigation == TAA_MITIGATION_AUTO)

	if (taa_mitigation == TAA_MITIGATION_AUTO) {

		if (should_mitigate_vuln(X86_BUG_TAA))

			taa_mitigation = TAA_MITIGATION_VERW;

		else

			taa_mitigation = TAA_MITIGATION_OFF;

	}



	if (taa_mitigation != TAA_MITIGATION_OFF)

		verw_clear_cpu_buf_mitigation_selected = true;
@@ -551,7 +552,7 @@ static void __init taa_select_mitigation(void) 


static void __init taa_update_mitigation(void)

{

	if (!taa_vulnerable() || cpu_mitigations_off())

	if (!taa_vulnerable())

		return;



	if (verw_clear_cpu_buf_mitigation_selected)
@@ -592,7 +593,7 @@ static void __init taa_apply_mitigation(void) 
		 */

		setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF);



		if (taa_nosmt || cpu_mitigations_auto_nosmt())

		if (taa_nosmt || smt_mitigations == SMT_MITIGATIONS_ON)

			cpu_smt_disable(false);

	}

}